Eye protection light is not the brighter the better

When parents choose eye protection lamps for their children, they often think that the brighter the light, the better. This reminds me of the story in the 90s when we thought that the whiter the flour, the better. Now everyone knows that the whitening of flour is due to the addition of brighteners. , Brighteners are harmful to people. Just like an eye protection lamp, judging whether a thing is good or bad must be determined by knowing its internal composition. Here I will talk about the basic knowledge of light source. The eye protection lamp protects the eyes because the high-frequency rectifier circuit makes people not feel the flicker of fluorescence. This is Philips technology in the 1980s, and now all large and small manufacturers can do it. The key to the eye protection effect of the eye protection lamp lies in the color rendering of the eye protection lamp tube and the color temperature of the lamp tube. The eye protection lamp uses a fluorescent tube. The main luminescent materials currently used are 1, pure three-base toner, 2, halogen powder, and 3, a mixed powder of the two. According to the cost calculation, the eye protection lamp with a retail price of less than 100 yuan in the market can basically not be called an eye protection lamp, because the eye protection lamp that is not a pure tri-color is actually a harmful eye lamp. The effect of the eye. (The price of pure tri-basic toner is nearly 10 times that of halogen powder) I will not analyze it here. I will only talk about the color temperature of the pure tri-basic toner tube. The light of the tri-color tube is the phosphor yttrium oxide (red light, peak wavelength is 611nm) that can emit red, green, and blue light sensitive to the human eye, and magnesium polyaluminate (green light, peak wavelength is 541nm) ) And barium magnesium polyaluminate (blue light, peak wavelength of 450nm) mixed into three primary color phosphors in a certain proportion, which emits light closer to sunlight. Color temperature is the human eye’s perception of a luminous body or a white reflector. Normally, from 10 noon to 2 pm, a clear and cloudless sky, in the absence of direct sunlight, the standard daylight is about 5000--5500K. But the light at this time is the most poisonous and dazzling. (See the part where the white light is close to the blue in the picture below). Current energy-saving lamps generally use a color temperature of 5500-6500K, and eye protection lamps generally use a color temperature of 4500--5500K. Many of our consumers feel eye pain after reading under a desk lamp. The reason is that the color temperature and color rendering of the desk lamp are not good. Suitable for reading at close range. It is easy to compare the same book under different color temperature lights. The higher the color temperature, the brighter the light, and the more dazzling the reflected light of writing. The lower the color temperature, the warmer the yellow light and the softer the reflected light of writing. , The less irritation to the eyes. Through experiments, we can see that the effect of reading books is the best when the color temperature is around 4000K, and there is basically no reflected glare. And why only a few manufacturers use 4000K color temperature lamps, there are only two reasons: one is that the higher the color temperature of the lamp, the cheaper it is, and the second is that the higher the color temperature, the brighter the light looks, just like a brightener. Like flour, it looks good! Therefore, remind users of table lamps and eye protection lamps that the brighter the table light line is, the better. The light for reading and learning should be soft. The standard color temperature is between 3800--4200K. It is the most suitable.